The Catalaphyllia corals, like other large polyp stony (LPS) corals, have developed several feeding strategies. Through a symbiotic relationship with a marine algae, known as zooxanthellae, they receive many of their nutrients. They also capture planktonic organisms, food particles from the water column, and can absorb dissolved organic matter.
In captivity, these corals are hungry all the time, so feed as needed with various types of foods for optimal health. Never feed your C. jardenei foods that are any larger than .25" (6 mm). Try mysis, krill, brine shrimp and other smaller items. You can also mince a small fish or shrimp into very small pieces and feed the entire organism to your Elegance Coral, since different parts of the animal have varying nutritional qualities. Just be cautious, placing a whole fish or shrimp does result in the animal's grabbing the food, but late at night it is regurgitated. This results in eventual starvation, starting with tissue recession and onset of possible disease. The C. jardenei does eat a lot of food, but it must be the proper small size of 1/4" or smaller.